CODEWITHSUNDEEP
cunix
anarhikos
anarhikos

Reputation: 1455

Is it possible getting and setting file name with struct stat descriptor?

Is it possible at get or set ( rename ) a file name with giving the absolute path of file, and a struct stat instance as parameters to lstat function. As I find in documentation struct seems like that; 

struct stat {
    dev_t     st_dev;     /* ID of device containing file */
    ino_t     st_ino;     /* inode number */
    mode_t    st_mode;    /* protection */
    nlink_t   st_nlink;   /* number of hard links */
    uid_t     st_uid;     /* user ID of owner */
    gid_t     st_gid;     /* group ID of owner */
    dev_t     st_rdev;    /* device ID (if special file) */
    off_t     st_size;    /* total size, in bytes */
    blksize_t st_blksize; /* blocksize for filesystem I/O */
    blkcnt_t  st_blocks;  /* number of blocks allocated */
    time_t    st_atime;   /* time of last access */
    time_t    st_mtime;   /* time of last modification */
    time_t    st_ctime;   /* time of last status change */
};

What I want is something like that; 

struct stat *s;
char *path; // assigning the ablosute path of file
int res = lstat(path, s);
if(res == -1)
   return errno;
char *name = s->(someFielAboutFileName);
or
s->(someFieldAboutFileName) = name; // setting name

Upvotes: 5

Views: 9014

Answers (3)

Frédéric Hamidi
Frédéric Hamidi

Reputation: 262919

It seems that you want to modify a symbolic link. lstat() won't help you with that, as it only returns the status of the link, not even the name of the file it points to, and cannot be used to modify anything about the file anyway.

You'll probably have to unlink() the symbolic link, then call symlink() to recreate it and make it point to the other file:

unlink(path);
symlink(name, path);

Upvotes: 0

StasM
StasM

Reputation: 10992

In Unix, the name of the file belongs to the directory, not the file. Meaning, the same file can have multiple names (it's called "hard links" in Unix). This also means you can not find out the name from stat, since it deals with files, not names. You can use realpath to find real name of the file, with resolving symlinks, etc.

Upvotes: 1

wnoise
wnoise

Reputation: 9922

No. In unix, the name is not an inherent property of the file. A file can have multiple names (see hard links) or even none.

The names are just entries in directories.

Upvotes: 3

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